Field of the Invention
The present invention relates to an alignment sleeve assembly and a fiber optic adapter comprising the alignment sleeve assembly.
Description of the Related Art
In the prior art, a fiber optic adapter (for convenience of description, herein take a single-fiber SC adapter as an example) generally comprises an alignment sleeve, a mating retainer for receiving the alignment sleeve therein and locking a pair of coupled fiber optic connectors, a housing, a buckle type fixing clamp spring and a warranty buckle (optional).
In the prior art, there is machining error in the alignment sleeve, for example, inner wall roundness of the alignment sleeve is not enough, and wall thickness of the alignment sleeve is not uniform. As a result, when ferrules of a pair of fiber optic connectors are inserted into the alignment sleeve of the fiber optic adapter from opposite ends of the alignment sleeve and coupled with each other, in addition to an alignment error, which will lead to a connection loss, between fiber cores of the coupled connectors, the alignment sleeve will also cause a certain alignment error, it will further increase the connection loss or increase the connection loss uncertainty. For an individual alignment sleeve, only when the alignment sleeve is located at a particular circumferential angle, the connection loss caused by it is minimal.
In the prior art, for batch manufacturing, the particular circumferential angle of each individual alignment sleeve corresponding to the minimum connection loss is apt to be different. Furthermore, the alignment sleeve is not positioned and fixed in the circumferential direction, and the alignment sleeve may rotate randomly. Therefore, minimizing the connection loss by positioned the alignment sleeve at the particular circumferential angle is not recognized and well utilized yet by the existing design.
As for the fiber optic adapter in the prior art, the alignment sleeve may freely rotate in the mating retainer along the circumferential direction and have a certain degree of freedom in three directions perpendicular to each other. Since the alignment sleeve has a certain tolerance, the connection loss of the coupled connectors has certain polarity. That is, only when the alignment sleeve is positioned at the particular circumferential angle, the coupled connectors may achieve the minimum insertion loss. However, in the prior art, the alignment sleeve may be rotated randomly. Thereby, the insertion loss of the entire optical fiber interconnection system is not always kept in a state of minimum loss. In other words, the random nature of the circumferential angle of the alignment sleeve affects the total insertion loss of the fiber interconnection system. Such situation does not meet strict requirements on ultra low insertion loss of optical fiber interconnection system in future and requirements on the repeatability of the ultra low insertion loss after the fiber optic connectors are decoupled.